Guild Wars 2

Here is some background story. I play since head-start and I got to lvl 80 in a matter of week or less not sure :X
Anyhow I had done my storyline and my girlfriend was slowly catching up. At level 55 she asked me to help her out in “Light in the darkness” story ( Yes, some of you might know where Im heading ).
Anyhow we fought our way through until we reached the “final stage” and for once I stopped to look around and just enjoy the game and then I heard it _ That awesome soundtrack :X
http://www.youtube.com/watch?v=bxa8go0NCBA

So here is my question. What is the name of this song and where do I find it ? Is it in the soundtrack CD from collector’s edition ?
I did some searching on iTunes for the full version of it but :/ I guess the song is not there.

So yes … where do I find this song. I don’t mind to buy my MP3s so a legitimate way is, of course, a way for me.

Thank you in advance.

P.S: Yes I’m more looking forward for a “Full-Version” rather than this ripped from the game client 1.30 audio file :|

This song is on the 4 CD set, not sure about the collector’s edition CD (don’t have it). Don’t remember what track but I do remember the epicness. I’m fairly certain it’s on the first CD, but not 100% sure. Haven’t done that quest yet, thank you for telling me which quest has this epic music.

Found a list of the songs on the wiki. This is the 2nd track on the first disk called “The Seraph”

I found that the “Seraph” track on the CD is really just the same as the ripped version played twice, with a little transition to smooth things out.